Compressor



May 11, 1954 G. F. PFEIFER 2,673,157

COMPRESSOR Filed June 19, 1951 5 Sheets-Sheet 1 a m m J m 1 mW A w 6 1;; z a 1 1 F 0 1 9 e 2 A .1 N\\\ N & w 9

y 11, 1954 G. F. PFEIFER 2,678,157

COMPRESSOR Filed June 19, 1951 5 Sheets-Sheet 2 ATTD RN EYS y 1, 1954 G. F. PFEIFER 2,678,157

COMPRESSOR Filed June 19, 1951 s Sheets-Sheet 3 rllfllll t V fl///////////./ A

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ATTD RN EYS May 11, 1954 Filed June 19,

G. F; PFEIFER COMPRESSOR 5 Sheets-Sheet 4 INVENTOR.

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ATTD RN EYS May 11, 1954 PFElFER 2,678,157

COMPRESSOR Filed June 19. 1951 5 Sheets-Sheet 5 [N VEN TOR.

ATTD RN EYS Patented May 11, 1954 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a compressor for air or other gaseous medium, and more particularly to a lubricating system for such a compressor.

The object of the invention is to provide a lubricating system for a compressor which will insure that the compressor operates quietly, efiiciently,

and wherein hydraulic hammer will be eliminated.

Another object of the invention is to provide a compressor lubricating system which is constructed so that the compressor will operate without noise, the system of the present invention utilizing a plunger pump which draws in a small amount of air with the oil being pumped, the air acting as a cushion to thereby eliminate hydraulic hammer within the pump cylinder.

Still another object of the invention is to provide a compressor lubricating system which includes a spring loaded, adjustable by-pass mechanism for regulating the oil pressure as the oil leaves the pump, the lubricating system of the present invention including a pressure gauge which is of simple and rugged construction and wherein the gauge is provided with stop mechanism for preventing damage to the gauge in the event the oil pressure exceeds a predetermined degree.

A further object of the invention is to provide a lubricating system for the compressor which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

Figure 1 is a fragmentary end elevational view of a compressor provided with the lubrication system of the present invention;

Figure 2 is a sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a sectional view taken on the line 3-3 of Figure 2;

Figure 4 is a sectional view taken on the line 44 of Figure 2;

Figure 5 is an enlarged sectional view taken on the line 5-5 of Figure 1;

Figure 6, is a sectional view taken on the line 6-6 of Figure 1;

Figure 7 is a sectional view taken on the line (-1 of Figure 1;

Figure 8 is an enlarged front elevational view of the pressure gauge;

Figure 9 is an enlarged fragmentary sectional view taken through the plunger and valve assembly;

Figure 10 is a sectional view taken on the line Ill-l0 of Figure 9;

Figure 11 is a sectional view taken on the line |l-Il of Figure 9.

Figure 12 is a sectional view taken on the line l2l2 of Figure 2.

Referring in detail to the drawings, the numeral l0 designates a crank case which forms part of a compressor, and the crank case [6 includes a bottom wall I I and vertically disposed end walls I2 and I4, Figures 1 and 2. The case It! further includes vertically disposed, spaced side walls 15, and a horizontally disposed top wall I 6. Mounted in the end wall I2 is a bearing race l1, and a plate I8 is detachably connected to the end wall I 4 by suitable screws or bolts I9. The plate 18 provides a support for a bearing race 20, Figure 2.

The present invention is directed to a lubrication system for a compressor, such as a com.- pressor used in compressing air, and the lubrication system includes a crankshaft which is indicated generally by the numeral 2|. The crankshaft 2! includes a pair of cylindrical end portions 22 and 23, the end portion 22 being rotatably supported in the bearing race 26, while the end portion 23 is rotatably supported in the bearing race H. The crankshaft is further provided with a pair of webs 24 and 25 which are spaced from each other, and arranged between the webs 24 and 25 is a pair of crank pins or eccentric sections 26 and 21, the sections 26 and 21 being ar ranged off center with respect to the longitudinal axis of the crankshaft 2|. A bearing 22 is arranged in engagement with each of the eccentric sections 26 and 21, and the lower ends of the usual connecting rods 29 engage the bearing 28. The upper ends of the connecting rods 29 are connected to the usual pistons for compressing air during the reciprocation thereof.

Arranged between the pair of eccentric sections 26 and 21 and formed integrally with the crankshaft 2| is an offset portion 30, Figure 3. Rotatably embracing or engaging the offset portion 30 is a strap 3|, the strap 3| including a pair of sections 32 that are detachably connected together by a bolt 33. Strap 3| is provided with a socket 34 which receives therein the head 35 of a movable plunger 36. A bolt or screw 31 serves to maintain the plunger 36 connected to the strap 3|. Thus, upon rotation of the crankshaft 2|, the plunger 36 will be caused to reciprocate. This is due to the fact that the center of the ofiset portion is offset from the center of the crankshaft, as best seen in Figure 3.

Extending into the case NJ is a fulcrumed bearing shaft or pin 38, Figure 2. The pin 38 includes an exteriorly threaded portion 39 that is arranged in threaded engagement with the end wall M of the case !0, and the pin 38 'is further provided with a head 40 which is adapted to be engaged by a suitable tool, such as a wrench, for removing or: replacing the pin 38. The pin 38 is provided with a bore 4! that extends longitudinally therethrough for a portion of its length,

and a plurality of radially extending ports 52 communicate with the bore 4!, there being. a.

gasket 43 interposed between the head 4fil'and' the adjacent portion of the crankcase. T-he 'pin.

38 is further provided with an annular groove The ports 45 which communicate with the bore 4!, and an annular groove 46.communicateswith-the outer. ends of theports 45. Anopening 4'! ex tends through a portion of the pump body. 49, the opening 41.. connectingjthe groove. 46..to a passageway 48 which is arranged invthe-pump body.

The body 49 is further providedwith a shoulder .50-, and mounted onthe shoulder 53 1s ascreen 5| which serves as a filter element, so, that oil whichis being. pumped fromthe-case ill. will be filtered. Theoil that is being pumped. enters the body 49 througha passageway52, and. communicating. withpassageway 52, is a-.bore..53 and vent 54, the vent 54 being. arranged inenga l ment with the bore. 52 .the body 49, Figures 2 and..9, the ventbeingprovided for. the ingress therethrough. of air... As, later, described in this application,. during. reciprocation of the plunger 36,,a small amountofair. willbe drawn. into the 7 pump. body through. the. opening or. vent. 54,

whereby the. air. will. becomeintermixed with oil passing, through the lubricating. system, so that the air will act. asfla cushion and help. eliminate noise.

The plunger 361s hollow or is provided witha chamber 55, Figures-.9, 1.0.. and. 11, .and'a plurality of ports. 56' communicate .with the chamber 55, the ports 56., terminating in an annular qgroove 5l'thatis arrangedin theplunger 36.1. A portion of the annular. groove 5'l-is. at all times .incomii munication withthe passageway 48. Whenthe vp11'1nger3liis movingv to its downwardjpositionoil will be forced. from the. chamber. 55 through the .porttl, then through ports 56', throughthe groove 5! and into .thepassageway 4.8.. Arranged in, the. lower, end of" the. plunger. 33.15. a. valve assembly which .includes .a. first valve 53 that is provided With..a..plurality of.cut.away portions 59i Valve.58'is mounted/for movement into and outof'bridgingrelation with respect'to a valve seat'fiflgand the valveseat 60 isprovided-with a central opening: 6| for the ingress therethrough a valve 66, the valve"66 having-the same construction" asthe previously-described. valve 58.

The'valve 66is shownv in detail-in-Figure 10', and

the valve 66 is provided with a plurality of cutouts or cut away portions 61, so that when the valve 66 is in its raised position during the up stroke of the plunger 36, oil will flow from the chamber past the cutout 61 and then into the oil chamber 55', due to the creation of a vacuum. A washer 68 is arranged contiguous to the upper surface of the valve seat 62 for maintaining the valve 66 in its proper spaced position.

Arranged in the platewor bearing carrier I8 is a chamber 69', Figure 2, and the chamber 69 has a bore 10 communicating there with for conveying oil thereto. The bore 10 communicates witha bore H which is arranged in the end wall'l4, and the bore ll communicates with the annular groove 44. Thus, lubricating oil will pass fromthe, pin.38 through the bores into the chamber '69. This lubricating oil will then pass through a passageway 12 which is arranged in the crankshaft 2|, and :'from the passageway 12 the lubricating oil is. forced. through .a. .passageway 13 into. apassageway or bore 14.-which is arranged in thecrankshaft 21. Aportion of :the lubricating oil will pass from the passageway 14 through channelways. 1.5 and. 16, whereby the. oil will conveniently lubricate the lower .partsof, the connecting rods.

A spring loaded,. ,adjustablebypass. is. provided for regulating the oil pressure in the system after .the oil leaves the pump Thus,'.all,.oil.which is in excess of the. required amount willbe re.- turned to the case sump. This .bypass..mecha.- nism is shown in detail in Figure 7, andcompr-ises an. adjusting. screw 11 which. is arranged. in threaded. engagement withthe. bearingcarrier E8. The adjustingscrew "is provided .with a chamber 18, and. the stem-..'I9..of a. valve ..80. is slidably arranged in .the chamber. 1.8- The ad justing screw 11. projects. into. av compartment 8| which is formed in the bearingcarrie'r 8,; and the compartment. vis connected tothechamber 69 by means of an opening. or. port 82... An, inclined port 83 leadsfrom-the compartmentflito the interior ofthe. case. 10.. Carried .-.by.the,.ad.- justing screw 1'! is apacking ring .84 whichserves to prevent oil leakage, andaspringBfi normally urges the valve 80. into bridging relationjwith respect to the opening 82, there being a nut 85 for locking: theadjusting. screw 1.1. in. place. Thus, in the. event the. oilpressure exceeds a predetermined..value,..the..valve 80.. will bemoved downwardly, so that oil can flow from thechamber 69. through the. port- 82-, then. throughthe port .83 back into. the .-sump-. The tension .on. the valve. 83 can. be. adjusted byrotating. or. varying the position of the adjustingscrew T1.

The assembly of thepresentinvention further includes an oil pressure gauge which is simple and fool-proof, and. thisgaugeis shown .in .detail in Figures 5,. 6 and 8.. Thus, .arrangedin. the bearing carrier [8. is a,.bore. .811. whichreceives. oil from a loore 7H. Thisoil then flows fromthe bore 8'! into a passageway 83, and thencetheoil flows through a felt dampening,.member 89, ,so,.that

F pulsation in the flowing oil willlbe'substantially reduced or. eliminated before. the oil: acts. on: the gauge plunger. The felt dampeninglpada89 is retained in its .properplaceby-means of .ascrew plug 35, Figure 6. The lubricating. oil then.-.flows into a compartment 3-! .to .urge. the plunger. .01" pistOIlfiZdlpWEtIdiY against the tension of-fla coil spring 93. The co il..spring- ,93. has. the proper tension to correspond with the oilpressure and gauge reading- The upper end of the'plung er.93 is arranged-in engagementwith a screw'plug'fit,

and the plunger 92 is provided with an annular groove 95. A port 96 communicates with the groove 95, whereby any oil that enters the annular groove 95 will be drawn back into the case I0. The crankcase is provided with a breather valve 98 which may be made of flexible material, and a stop member 91 serves to limit upward flexing movement of the valve 98. The members 91 and 98 are maintained in their proper position by means of a screw or bolt 99. The breather valve 98 thus causes the pressure inside the crankcase.

to be slightly lower than atmospheric pressure, since the movement of the compressor pistons cause the breather valve 98 to open and close. Therefore, as previously stated, any oil which enters the groove 95 in the plunger 92 will be drawn back into the case rather than escape past the plunger 92.

The gauge further includes a dial I00, the dial I being provided with suitable numerical graduations for indicating the oil pressure, as shown in Figures 1 and 8. A pointer arm IOI is arranged to move relative to the dial I00, and the pointer arm MI is provided with, or has secured thereto, an extension pin I02 which projects into a groove I03 that is arranged in the plunger 92, Figure 6. Thus, as the plunger 92 moves up and down, the pointer arm IIlI will be caused to move. The spring 93 is tensioned so that the movement of the plunger 92 will give a proper reading on the dial I09. The dial I00 is further provided with a lug I04, Figure 5, and the lug I04 is seated in a groove which is arranged in dial cover I05. A glass disc I 86 is arranged between the dial I00 and the cover I05, and the dial, groove and cover assembly is fastened or secured to the bearing carrier by a plurality of suitable securing elements, such as screws I01.

A stop means is provided for preventing damage to the gauge in the event the pressure in the system exceeds a predetermined amount. This stop means comprises an annular flange I08 which is formed integrally with or secured to the plunger 92, and the annular flange I08 will abut a portion of the bearing carrier I8 to limit downward movement of the plunger 92. For limiting upward movement of the plunger 92,

, the screw plug 94 will be contacted by the upper end of the plunger 92. A passageway II2 extends from the passageway 14, whereby some of the lubricating oil can be used for lubricating the parts of the pump adjacent to the offset portion 30, Figure 3. A drain plug I09 is detachably connected to the crankcase, whereby the oil can be drained from the crankcase when I desired.

The operation of the lubricating system of the present invention is as follows: The crankshaft 2| is rotated by any suitable means, and this imparts a reciprocating motion to the plunger 36. Then, on the up stroke the oil will flow from the sump or case through the screen then through the bore 52, and into the body 49. This lubricating oil will then enter the annular space 64 which is formed by the valve seat 52, and this will then flow through the ports .63 in the seat 62 and enter the pump cylinder by passing through the cutout portions 61 in the valve 59. The valve 65 is raised slightly during the up stroke of the plunger due to vacuum. The diameter of the plunger 36 and stroke of the offset portion 39 are so proportioned that the oil cannot flow fast enough through the bore 52 to fill the cylinder 55' to full capacity. This means that the pump is trying to fill, but is re- 6 strained, so that air will be drawn through the bore 53, then through the bore 54, and this air will become intermingled or intermixed with the lubricating oil.

On the downward stroke of the plunger 36, the entrapped air in the pump cylinder acts as a resilient force at the beginning of the stroke, thereby eliminating the hydraulic hammer that is usually associated with high speed plunger pumps. The oil and air which are intermixed then flow through the openings 6| in the valve seat 69, and this oil flows around the wing guides or through the cutout portions 59 in the valve 58. This oil and air flows into the space 55 and then through the ports 56 into the annular space 51. The oil and air then flow through the bore 49, and then through the opening 41 into the fulcrum shaft 38. Then, the lubricating oil flows through the bores II and 18 and into the chamber 69 which is arranged in the bearing carrier I8. This lubricating oil then goes through the distributing ducts or passageways into the crank shaft 2I and then to the connecting rod bear-.

ings. The spray from the crank pins and connecting rods provides lubrication for the upper ends of the rods and cylinders.

The chamber I I0 is normally filled with air at atmospheric pressure, but as soon as the pump delivers oil, the entrapped air in the chamber I I0 will be alternately compressed and expanded to thereby eliminate most of the pulsations in the oil line. The pressure setting at which the system is set to operate is controlled by the bypass valve which is slidably mounted in the adjusting screw 11. The screw TI is locked in place by the nut 85, and the screw 11 is provided with the packing ring 84, Figure '7, for preventing oil leakage. The oil pump body 49 is provided with a vent I I I, Figure 2, and the vent I I I prevents the oil that escapes past the end of the fulcrum shaft 38 from building up pressure and thereby moving the pump laterally. The duct 81 in the bearing carrier I8 is arranged in alignment with the ports 'II in the case I0, and lubrieating oil is fed through the dampening felt pad 89 to the under side of the gauge plunger 92, thus forcing the gauge plunger 92 upward against the tension of the spring 93. The plunger 92: is provided with the annular space which aligns with the vent hole 98 in the carrier I8.

Dial I00 on the indicating gauge is provided with numerical graduations for indicating the oil pressure, and the pointer arm I8I is mounted for movement relative to the dial I00. The pointer arm IOI has secured thereto the extension pin I02 which projects into the groove I03 in the plunger 92. Thus, as the plunger 92 moves up or down, this movement will be transmitted to the pointer arm NH. The spring 93 is tensioned so that the movement of the plunger 92 gives the proper gauge reading. The screw plug 94 serves to limit up travel of the plunger 92, so that damage to the gauge will be prevented in the event the oil pressure exceeds the setting of the bypass valve.

\ Further, the movements of: the compressor system cause the breather valve 98 to alternately open and close with respect to the breather opening therebelow. Thus, the pressure inside the case I0 will be slightly lower than atmospheric pressure, and this reduced pressure in the case causes any oil that works past the plunger 92 into the groove 95 to flow through the ports 96 back into the case. Also, the intake valve 65 and the exhaust valve 58 are of identical construction,

solithat. the:;lifat;can be held .to avminimuni. and:

therefore-these valves will bequiet in operatioru;

From: the foregoing it Y isnapparent. that a labricating system for a compresso-rhasibeen providedewhereby' the oil is supplied under pressure by aaplunger-typeuoil pump which includes; both inletxxand exhaustvalves; The construction of the:pump-is such that :it is=quiet running. and en'-. tirely'free from hydraulic hammer. Theplungertype." oil; pump Will function efiiciently eventhough' the" compressors are 1 operated in alternate*directions.andgiurther, the hydraulic hammerwil'lf be eliminated even though the pump. may be-operating at a1high speed, or even though the compressorsmazybe operating: at a high rate. Thus; ordinarily; a definite hydraulic hammer issset" up in. the conventional pump momentarily when .the plunger changes. from the inlet to the exhaust'motion, due to theiact that the oil isat rest'zmomentarilyzat'the end of: theinlet stroke and mustbe started in an opposite flow. Thus, atith-isstime the -.oil' is-in a moreror less solidjcondition whenatheihydraulic hammer occurs. The systemzof the present invention overcomes this hamrnerandxelimihates the noise set up by uncovering an inlet port-atthe endof the-inlet stroke, since-the pump. of.- the :present :ihvention is.equipped; with :anzinlet valveas well as an ex.- haustivalve, and also, the stroke of the plunger is; sufficientlygreat-"so that the. piston: displacementfof the pumpiis greater'than that required for the amount ofjoilineeded, and further, the inl'eupassagesiarel restricted solthat at no time Will thenpumpscylirrderz beentirely filled: with oil. Thus; the bore53ispermits air toenterithe vent :54 which is. connectediao the inlet; passageway: 52 '80: thatza.v small amount: of: air; will: be taken. in. :with the oil. at each; stroke; and. this air; then adds to .1 the :;cushion; when; the .plunger changes-from inlet to: exhaust "str'oke-,. to; thereby eliminate? all hydraulic hammer; semup: within the pump cylinder: Further; thenspring loaded, adjustable: Icy-pass is providedfiorregnlatingthe oil: pressure after .leaving the: pump; 'Oili in excessnfzthe required'amount is returned tol the case sump; 1

Also, the built-in oil pressure gaugerissimple and" foolproof; andrtheo il" is: delivered tothe underv side of' the spring loaded -plun'gerI92- which a the pulsation in-theoilline. Tofurther'reduce' pulsations of theoilacting on theigaugeplunger 92,-:thei-length-of felt 89 is. used which can be compressedslightly-during assembly, to thereby further: dampenoutpulsations on the plunger 92 and other parts of the oil gauge. The seat 60 canibe heldin place on the bottom of the plunger 3g6ibyzro llinggor swedging the'edge of the plunger 36', and the r valve and seat thereb'elow can also 8?, berheld. in..placeby rolling lore swedgine ortions. of". the 1' pump body 49.-

What is claimed. is:

1. In an :air comppessor, aecase: providedvwith' a-bottom wall, spaced parallel; sidezawa-llsaspaced parallel end walls and; a top; wall, a sbea-ring race mounted in one of said end walls, aabearingeca-re rier. detachably connectedyto the other: endziwa'l'li and? arranged in opposed relation. withrespect to:said'bearing race, .a bearing racemounted said. bearing carrier,; acrankshaft: having-fits ends-rotatably'supportedeby said pair of bearing races, a pair ofeccentric: sectionsiarrarigedaom saidf. crankshaft, connecting rods; having their. lower ends pivot-ally.connected: to saideccentnic sections; an intermediate; offset portion: arranged be tween saidtpair of "eccentric:sections; the center. of said oiiset portion being oiiset withnrespectzto the center of "the crankshafui there being inter- 7 groove communicating with said. ports, .a' pumpbody mounted onthe. inner endtoi said: pinand provided with a; cylinder for slidably receiving. said plunger; said pump. body having-'a passagea Way connected. to. said; groove, conduit .means. in

sat-cl body, Dllli' and bearing earrier-forconveying:

oil to the passageways-in.said-crankshaft; a-zvent in said body for intermixing air with-the 'oilrfiow; ingthrough'the system, a-pluralityaof valves arrang ed inzthe lower end of said plunger for: .regue 1" ing theyiiou; oiwcilxthrough the. pump bodyya reticulatedelement mounted on said'f body for filtering the: oil flowing: into::the body, and. a spring.loaded'adjustable bypass valve includingv antadiusting screw arranged in engagement with saidbearing carrier forregulating the oilpres-i sure'in the systemafterthe oil leavesthe'pump.

2. The apparatus. asdescribed' in claim 1, and further including a vent arranged in saidpump body for preventing oil that escapes'past the end of'ithe fulcrumed pin from building up: pressure and moving the pump laterally.

3', The apparatus-as described in claim-1:, and further including a 'gaugemounted inv an .end of.- said' case; for: indicating .the oil pressure in: the: system, stop means for preventing damage-to the gauge in-ther eventpressure in .the systemxiexceeds :sazpredetermined 1 amount, the pressure in side thecase beingslightlyvlower thanxatmos phe l0 pressure, and?v a dampening member for reducing; pulsations in the" flowing": oil;

' References Cited-in the-file ofithis patent UNITED STATES PATENTS 

